Observation of domain structure in 001 orientated NaNbO3 films deposited on (001)SrTiO3 substrates by laser beam scanning microscopy

A laser beam scanning microscope (LSM) was used to observe the domain structure of 001 orientated NaNbO3 (NN) films on SrRuO3/(001)SrTiO3 substrates. The LSM micrograph clearly showed the domains and the domain walls of NN film. Using a polarization plate revealed that the deposited NN film had antiferroelectric 90° domains separated by {100} domain walls. When 001 orientated NN film was applied by an electric field, the 90° domains and the {100} domain walls disappeared and a new domain structure and {110} domain walls were created. This drastic change is due to the formation of new 60° domains.